Fossils are a faithful recording of ......54....... an accurate imprint of the past. .......55....... imagine a prehistoric fish swimming around in the sea a few million years ago. One day, the fish dies .....56...... its body sinks down to the water bottom, where it becomes buried in soft mud.
......57....... time passes, the flesh decays, and ......58...... An imprint of the skeleton stays in the mud, even after the skeleton itself disintegrates. Many years pass. The mud with .....59..... gradually hardens and turns to stone under the pressure of the rock layers that have subsequently built up on .......60......